Rear Axle Gauging

What are the leading wheel alignment factors?

Wheel alignment is the positioning of the interrelated angles of a front suspension, rear axle or housing to give the maximum amount of tire life, steering ease, steering stability and increased life of suspension components. Improper wheel alignment results in excessive or irregular tire wear, hard steering, poor drivability and premature failure of suspension parts. Several alignment factors must be considered to achieve proper wheel alignment. The top four factors are toe, tracking, camber and caster.

Toe and tracking are the two most critical alignment settings for front end tire wear. Bee Line gauging equipment incorporates lasers to measure for proper steer axle toe. Toe is adjustable to reduce tire wear and shimmy in the steering wheel. Excess or too little toe will make the front wheels fight each other, resulting in feathering, diagonal wear or excessive shoulder wear.  An out-of-toe condition leads to rapid tire wear. Tracking misalignment also will cause inside outside wear of the steer tires. Tracking, or thrust, is gauged relative to the vehicle centerline.

Camber and caster are the third and fourth most critical alignment settings for front end tire wear. Camber — the inward or outward tilt of the top of the wheel — is important for several reasons. Its main purpose is to keep the tire flat on the road while the vehicle is loaded and in motion. If camber is excessive, it will create shoulder wear. Caster is the forward or rearward tilt of the king pin. Extreme caster settings can cause handling problems, leading to driver fatigue.

What does a pre-alignment check entail, and why is it important to tire life OR your customers?

Consistently practicing thorough pre-alignment inspections can lead to an increased bottom line for your company. When you perform these checks, you significantly decrease your chances of overlooking a problem that could cause your customer’s vehicle to have issues later, which could, in turn, lose business for you.

The first step in any pre-alignment inspection is to check and record the “cold” inflation pressure on each tire, typically after the vehicle has been at rest for several hours. Both steer tires should have roughly the same pressure, as should all drive tires and all trailer tires when compared to each other. Remember: No matter how precisely aligned the camber, caster, toe and tracking angles — the vehicle will still pull if there is uneven tire pressure.

Next steps involve checking the tires for irregular wear, including fast wear, feather wear, cupping, diagonal wear, rapid shoulder wear and one-sided wear. The type of tire wear patterns can indicate specific alignment problems; for example, a toe condition can quickly and easily be diagnosed if a technician notices steer tire feather wear to be in the same direction across the axle.

Also, make sure to check for problems like damaged springs, worn king pins, loose bearings or worn steering linkage in the suspension.

While all inspections may not be necessary, properly executed checks provide a courtesy to the customer that may increase satisfaction and confidence in your business. It also ensures that each and every vehicle serviced in your bay is evaluated in the same way.

The Bee Line LC7500 Computer Alignment System utilizes sensors and lasers to precisely gauge toe, tracking, caster and camber for a vehicle that is aligned better than new. It can be calibrated in a few minutes right in your shop and minimizes downtime, thus increasing your profit potential. For more information, visit www.beeline-co.com.